Vegetative propagation of some selected mangrove species from Negombo estuary, Sri Lanka

Khwl De Silva,Md Amarasinghe

doi:10.4038/sljas.v15i0.5480

Abstract

Mangrove forests are degraded and threatened worldwide, due to anthropogenic events. Mass production of planting material and successful germination of seeds are essential processes in rehabilitating these degraded mangrove forests. The present work was carried out to determine the efficacy of using propagule cuttings in mass production of plant materials and to determine the potential of using non mangrove soils to establish propagule cuttings for ornamental purposes. In addition air layering and stem cutting techniques were also tested for the mangrove propagation. Propagation of Rhizophora apiculata, by propagule cuttings, treated with root promoting hormones is feasible and it was possible to produce three saplings from one propagule. Indole Butyric Acid (IBA) (1000 ppm) was the best hormone concentration for inducing roots and IBA (1500 ppm) was the best for inducing shoots from propagule cuttings of R. apiculata. Air layering and stem cutting were performed with Avicennia marina and R. apiculata but none of the species was able to generate roots and therefore these vegetative propagation methods cannot be used for mass propagation of these mangrove species. Optimum growth medium and period of nursery care for mangrove saplings of R. apiculata, Ceriops tagal and Bruguiera sexangula were studied and the results revealed that best growth performance was in mangrove soils, i.e. 4.15 cm/ 4weeks for R. apiculata, 3.75 cm/ 4weeks for B. sexangula and 0.56 cm/ 4 weeks for C. tagal, while mangrove soils mixed with sand produced the second best growth for C. tagal and B. sexangula . Seedlings grown on terrestrial soils showed the lowest growth rate for all three mangrove species. However, no significant difference (P Potting media consisted only of mangrove soils as well as mangrove soils (1): sand (1), terrestrial soil alone and mangrove soil (1): terrestrial soil (1) can be used as nursery growth media for R. apiculata and C. tagal. DOI: http://dx.doi.org/10.4038/sljas.v15i0.5480 Sri Lanka J. Aquat. Sci. 15 (2010): p.25-38

Highlights

Over the past years, mangrove habitats have been severely degraded take place heavily throughout the world and it was estimated that about one-third of the world’s mangrove forests are lost due to a number of causes, of which, unrestricted clear felling, aquaculture, and overexploitation for fisheries will continue to be the greatest threats of mangrove forests in the 25 years (Alongi 2002)
Aegiceras corniculatum, Bruguiera sexangula, Ceriops tagal, Rhizophora apiculata and R. mucronata are the mangrove species investigated for the feasibility of vegetative propagation through air layering, stem cutting and propagule cutting supported with growth promoting hormones
Mean root and shoot lengths produced by various combinations of Indole Butyric Acid (IBA) and Naphthalene Acetic Acid (NAA) are graphically presented in Figures 1 and

Summary

Introduction

Mangrove habitats have been severely degraded take place heavily throughout the world and it was estimated that about one-third of the world’s mangrove forests are lost due to a number of causes, of which, unrestricted clear felling, aquaculture, and overexploitation for fisheries will continue to be the greatest threats of mangrove forests in the 25 years (Alongi 2002). This has led to considerable attention on mangrove regeneration both in national and global levels. It is believed that mangroves can propagate vegetatively through propagule cuttings too where propagules are cut into pieces and each one would grow into a sapling separately (Selvam et al 2005)

Methods

Results

Discussion

Conclusion